| 1. |
- Högman, Marieann, et al.
(författare)
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Effects of growth and aging on the reference values of pulmonary nitric oxide dynamics in healthy subjects
- 2017
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- The lung just like all other organs is affected by age. The lung matures by the age of 20 and age-related changes start around middle age, at 40-50 years. Exhaled nitric oxide (FENO) has been shown to be age, height and gender dependent. We hypothesize that the nitric oxide (NO) parameters alveolar NO (CANO), airway flux (JawNO), airway diffusing capacity (DawNO) and airway wall content (CawNO) will also demonstrate this dependence. Data from healthy subjects were gathered by the current authors from their earlier publications in which healthy individuals were included as control subjects. Healthy subjects (n = 433) ranged in age from 7 to 78 years. Age-stratified reference values of the NO parameters were significantly different. Gender differences were only observed in the 20-49 age group. The results from the multiple regression models in subjects older than 20 years revealed that age, height and gender interaction together explained 6% of variation in FENO at 50 ml s-1 (FENO50), 4% in JawNO, 16% in CawNO, 8% in DawNO and 12% in CANO. In conclusion, in this study we have generated reference values for NO parameters from an extended NO analysis of healthy subjects. This is important in order to be able to use these parameters in clinical practice.
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| 2. |
- Lindberg, Lars, et al.
(författare)
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The advantages of standardizing exhaled breath-alcohol concentration to a reference respiratory gas—water vapor
- 2023
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 17:1
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Forskningsöversikt (refereegranskat)abstract
- Measuring the concentration of alcohol (ethanol) in exhaled breath (BrAC) provides a rapid and non-invasive way to determine the co-existing concentration in arterial blood (A-BAC). The results of breath-alcohol testing are used worldwide as evidence of excessive drinking, such as when traffic offenders are prosecuted. Two types of breath-alcohol analyzer are in common use; hand-held instruments used as preliminary screening tests of sobriety and more sophisticated evidential instruments, the results of which are accepted as evidence for prosecution of drunken drivers. Most evidential breath-alcohol analyzers are designed to capture the last portion of a prolonged exhalation, which is thought to reflect the alcohol concentration in substantially alveolar air. The basic premise of breath-alcohol analysis is that there is a physiological relationship between A-BAC and BrAC and close agreement between the two analytical methods. This article reviews the principles and practice of breath-alcohol analysis and introduces the concept of standardizing the results to a secondary physiological gas (water vapor), which therefore serves as an internal standard. The measured BrAC is thus adjusted to an alveolar air water content of 43.95 mg l−1 at 37 °C. This has several advantages, and means that a sample of breath can be captured without the person having to blow directly into the instrument. Adjusting the breath-alcohol concentration to water vapor concentration also compensates for variations in temperature of the expired air. The contact-free method of sampling breath means that a mouthpiece is unnecessary and the test subject does not need to make a continuous end exhalation.
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| 3. |
- Bondesson, Eva, et al.
(författare)
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Exhaled breath condensate-site and mechanisms of formation
- 2009
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7163 .- 1752-7155. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Exhaled breath condensate (EBC) analysis is a promising tool for diagnosis and management of pulmonary diseases. Its clinical usefulness is still limited however due to unresolved issues around e. g. reproducibility, anatomical site of origin of EBC solutes and mechanisms of EBC formation. To gain some knowledge on these issues, three different airway deposition patterns of an aqueous aerosol containing technetium-99m were studied in eight healthy non-smoking subjects. EBC was collected 20 min after each radioaerosol administration and analyzed for gamma radiation and electrolytes. Radioaerosol deposition in preferentially central lung compared with preferentially peripheral lung resulted in 3.8 times higher EBC radioactivity. EBC concentrations of Na+ and K+ correlated significantly indicating dilution by water vapor to be a major source of variability. Since Na+/K+- and Na+/S2--concentration ratios, but not Na+/Cl--or Na+/Ca2+-, were comparable to those previously reported for alveolar lining fluid (ALF), some mechanisms other than dilution are likely also to be involved. In conclusion, our findings indicate that EBC derives mainly from the central airways, that the electrolyte composition of EBC does not consistently reflect that of ALF, and that EBC concentrations of electrolytes are determined not only by ALF dilution with water vapor but also by other mechanisms.
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| 4. |
- Lindberg, Lars, et al.
(författare)
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Simultaneously recorded single-exhalation profiles of ethanol, water vapour and CO2 in humans: impact of pharmacokinetic phases on ethanol airway exchange
- 2012
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7163 .- 1752-7155. ; 6:3
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Tidskriftsartikel (refereegranskat)abstract
- The breath alcohol concentration (BrAC) standardized to the alveolar water vapour concentration has been shown to closely predict the arterial blood alcohol (ethanol) concentration (ABAC). However, a transient increase in the ABAC/BrAC ratio has been noted, when alcohol is absorbed from the gastrointestinal tract (absorption phase) and the ABAC rapidly rises. We analysed the plot of simultaneously recorded alcohol, water vapour and CO2 against exhaled volume (volumetric expirogram) for respiratory dead space volume (VD), cumulative gas output and phase III slope within one breath to evaluate whether changes in the BrAC profile could explain this variability. Eight healthy subjects performed exhalations through pre-heated non-restrictive mouthpieces and the concentrations were measured by infrared absorption. In the absorption phase, the respiratory VD of alcohol was transiently increased and the exhaled alcohol was displaced to the latter part of the expirogram. In the post-absorption phase, the respiratory VD for alcohol and water vapour was stable and always less than the respiratory VD for CO2, indicating that the first part of the exhaled alcohol and water originated from the conducting airway. The position of the BrAC profile between water vapour and CO2 in the post-absorptive phase indicates an interaction within the conducting airway, probably including a deposition of alcohol onto the mucosa during exhalation. We conclude that the increase in the ABAC/BrAC ratio during the absorption phase of alcohol coincides with a transient increase in respiratory VD of alcohol and a delay in the appearance of alcohol in the exhaled air as the exhalation proceeds compared with the post-absorption phase.
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| 5. |
- Ghorbani, Ramin, 1981-, et al.
(författare)
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Fitting of single-exhalation profiles using a pulmonary gas exchange model : application to carbon monoxide
- 2019
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Ingår i: Journal of Breath Research. - : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- Real-time breath gas analysis coupled to gas exchange modeling is emerging as promising strategy to enhance the information gained from breath tests. It is shown for exhaled breath carbon monoxide (eCO), a potential biomarker for oxidative stress and respiratory diseases, that a weighted, nonlinear least-squares fit of simulated to measured expirograms can be used to extract physiological parameters, such as airway and alveolar concentrations and diffusing capacities. Experimental CO exhalation profiles are acquired with high time-resolution and precision using mid-infrared tunable diode laser absorption spectroscopy and online breath sampling. A trumpet model with axial diffusion is employed to generate eCO profiles based on measured exhalation flow rates and volumes. The concept is demonstrated on two healthy non-smokers exhaling at a flow rate of 250 ml s−1 during normal breathing and at 120 ml s−1 after 10 s of breath-holding. The obtained gas exchange parameters of the two subjects are in a similar range, but clearly distinguishable. Over a series of twenty consecutive expirograms, the intra-individual variation in the alveolar parameters is less than 6%. After a 2 h exposure to 10 ± 2 ppm CO, end-tidal and alveolar CO concentrations are significantly increased (by factors of 2.7 and 4.9 for the two subjects) and the airway CO concentration is slightly higher, while the alveolar diffusing capacity is unchanged compared to before exposure. Using model simulations, it is found that a three-fold increase in maximum airway CO flux and a reduction in alveolar diffusing capacity by 60% lead to clearly distinguishable changes in the exhalation profile shape. This suggests that extended breath CO analysis has clinical relevance in assessing airway inflammation and chronic obstructive pulmonary disease. Moreover, the novel methodology contributes to the standardization of real-time breath gas analysis.
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| 6. |
- Ghorbani, Ramin, 1981-, et al.
(författare)
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Impact of breath sampling on exhaled carbon monoxide
- 2020
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Ingår i: Journal of Breath Research. - : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- The influence of breath sampling on exhaled carbon monoxide (eCO) and related pulmonary gas exchange parameters is investigated in a study with 32 healthy non-smokers. Mid-infrared tunable diode laser absorption spectroscopy and well-controlled online sampling is used to precisely measure mouth- and nose-exhaled CO expirograms at exhalation flow rates (EFRs) of 250, 120 and 60 ml s−1, and for 10 s of breath-holding followed by exhalation at 120 ml s−1. A trumpet model with axial diffusion is employed to fit simulated exhalation profiles to the experimental expirograms, which provides equilibrium airway and alveolar CO concentrations and the average lung diffusing capacity in addition to end-tidal concentrations. For all breathing maneuvers, excellent agreement is found between mouth- and nose-exhaled end-tidal CO (ETCO), and the individual values for ETCO and alveolar diffusing capacity are consistent across maneuvers. The eCO parameters clearly show a dependence on EFR, where the lung diffusing capacity increases with EFR, while ETCO slightly decreases. End-tidal CO is largely independent of ambient air CO and alveolar diffusing capacity. While airway CO is slightly higher than, and correlates strongly with, ambient air CO, and there is a weak correlation with ETCO, the results point to negligible endogenous airway CO production in healthy subjects. An EFR of around 120 ml s−1 can be recommended for clinical eCO measurements. The employed method provides means to measure variations in endogenous CO, which can improve the interpretation of exhaled CO concentrations and the diagnostic value of eCO tests in clinical studies.Clinical trial registration number: 2017/306-31
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| 7. |
- Högman, Marieann
(författare)
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Innovative exhaled breath analysis with old breathing manoeuvres-is there a problem or an advantage?
- 2017
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- As the field of exhaled breath research is expanding, the question that arises is can the old usual method of spirometry be used in all cases? The answer is yes for some analysation methods and definitely not for others: it all depends on the result you are looking for. Exhaled breath condensate collection can be accomplished with silent tidal breathing, but not in the analysation of the amount of exhaled particles, as they become very low during tidal breathing. There are gases that are exhalation flow dependent, e.g. nitric oxide, acetone and ethanol, that require a special breathing manoeuvre with flow control. Physiological changes of the lung, i.e. inhalation to total lung capacity or forced exhalation such as during spirometry, will affect the result of exhaled biomarkers. The standardisation of exhaled breath requires further development, and there are many aspects to consider.
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| 8. |
- Högman, Marieann
(författare)
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Reference equations for exhaled nitric oxide-what is needed?
- 2024
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Ingår i: Journal of Breath Research. - : Institute of Physics (IOP). - 1752-7155 .- 1752-7163. ; 18:3
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Tidskriftsartikel (refereegranskat)abstract
- Standardisation is the road to improvement! If we all measure exhaled nitric oxide (NO) the same way, we will be successful in having data to make reference questions. Many research groups have published their reference equation, but most differ considerably. About 25 years ago, using the flow of 50 ml s(-1) was recommended and not using a nose clip. When collecting data worldwide, we still see publications that do not indicate what flow was used and that nose clip was utilised. Three things are needed: the analysing method, a flow recording and a filled-in nitric oxide questionnaire. The analysing method is because the techniques have different sensitivity, response times and calibration. The flow of 50 ml s(-1) is on the steep part of the NO output curve; therefore, we need to record the flow to analyse repeated measurements or compare results. The NO questionnaire controls individual factors that may influence the NO measurements, i.e. food intake, smoking and upper airway infection. An important tool in following old and new disease treatments, at home or in health care, is exhaled biomarkers. If we follow the standardisation we have agreed upon, we will be able to have data to say what a high or a low exhaled NO value is.
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| 9. |
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| 10. |
- Jacinto, Tiago, et al.
(författare)
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Differential effect of cigarette smoke exposure on exhaled nitric oxide and blood eosinophils in healthy and asthmatic individuals
- 2017
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Background:Tobacco smoking affects both the fraction of exhaled nitric oxide (FeNO) and blood eosinophil (B-Eos) count, two clinically useful biomarkers in respiratory disease that represent local and systemic type-2 inflammation, respectively.Objective:We aimed to study the influence of objectively measured smoke exposure on FeNO and B-Eos in a large population of subjects with and without asthma.Methods:We utilized the US National Health and Nutrition Examination Surveys 2007-2012 and included 10 669 subjects aged 6-80 years: 9869 controls and 800 asthmatics. Controls were defined as having no respiratory disease, no hay fever in the past year, and B-Eos count ≤0.3 × 109 l−1. Asthma was defined as self-reported current asthma and at least one episode of wheezing or an asthma attack in the past year, but no emphysema or chronic bronchitis. Tobacco use was collected via questionnaires and serum cotinine was measured with mass spectrometry.Results:Increasing cotinine levels were associated with a progressive reduction in FeNO in both controls and asthmatics. FeNO remained significantly higher in asthmatics than controls except in the highest cotinine decile, equivalent to an average reported consumption of 13 cigarettes/day. B-Eos count increased with cotinine in controls, but was unchanging in asthmatics. Interestingly, B-Eos count was significantly higher in presently non-exposed (cotinine below detection limit) former smokers than never smokers.Conclusion:Smoke exposure decreases FeNO and increases B-Eos count. These effects should be considered in the development of normalized values and their interpretation in clinical practice. The persistence of elevated B-Eos in former smokers warrants further studies.
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| 11. |
- Jõgi, Nils Oskar, et al.
(författare)
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Device comparison study to measure nasal nitric oxide in relation to primary ciliary dyskinesia
- 2024
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Ingår i: Journal of Breath Research. - : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Primary ciliary dyskinesia (PCD) is a genetic respiratory disease characterized by chronic cough, recurrent respiratory infections, and rhinosinusitis. The measurement of nasal nitric oxide (nNO) against resistance has been suggested as a sensitive screening method. However, current recommendations argue for the use of expensive, chemiluminescence devices to measure nNO. This study aimed to compare nNO measurement using three different devices in distinguishing PCD patients from healthy controls and cystic fibrosis (CF) patients and to evaluate their diagnostic precision. The study included 16 controls, 16 PCD patients, and 12 CF patients matched for age and sex. nNO measurements were performed using a chemiluminescence device (Eco Medics CLD 88sp), and two devices based on electrochemical sensors (Medisoft FeNO+ and NIOX Vero) following standardized guidelines. Correlation estimation, Bland-Altman, ROC curve, and one-way ANOVA were used to assess device differences and diagnostic performance. Significantly lower nNO output values were observed in PCD and CF patients compared to controls during exhalation against resistance. The correlation analysis showed high agreement among the three devices. ROC curve analysis demonstrated 100% sensitivity and specificity at different cut-off values for all devices in distinguishing PCD patients from controls (optimal cut-offs: EcoMedics 73, Medisoft 92 and NIOX 87 (nl min-1)). Higher nNO output values were obtained with the Medisoft and NIOX devices as compared to the EcoMedics device, with a bias of-19 nl min-1(95% CI: -73-35) and -21 nl min-1(-73-31) accordingly. These findings indicate that all three tested devices can potentially serve as diagnostic tools for PCD if device specific cut-off values are used. This last-mentioned aspect warrants further studies and consideration in defining optimal cut-offs for individual device.
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| 12. |
- Krantz, Christina, et al.
(författare)
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Exhaled and nasal nitric oxide in relation to lung function, blood cell counts and disease characteristics in cystic fibrosis
- 2017
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Patients with cystic fibrosis (CF) have similar or lower exhaled nitric oxide (FeNO) and lower nasal nitric oxide (nNO) levels than controls. There are divergent results on alveolar NO (CalvNO) concentrations in relation to CF. There are inconsistent results on correlation between different nitric oxide parameters and lung function and inflammation in CF.AIM: To compare FeNO, CalvNO and nNO levels between subjects with CF, asthma and healthy controls and to study whether these parameters are related to lung function, blood cell counts or clinical characteristics in CF patients.MATERIAL AND METHODS: Measurements of FeNO at multiple exhalation flow rates, nNO and spirometry were done in 38 patients (18 adults) with CF. Blood cell counts and CF clinical characteristics were recorded. Thirty-eight healthy controls and 38 asthma patients, gender- and age-matched, were included as reference groups.RESULTS: FeNO levels were lower in CF patients (7.2 [4.7-11.2] ppb) than in healthy controls (11.4 [8.3-14.6] ppb) and asthma patients (14.7 [8.7-24.7] ppb) (both p < 0.005). These differences were consistent in adults. No difference in CalvNO was seen between the groups. nNO levels in CF patients (319 [193-447] ppb) were lower than in healthy controls (797 [664-984] ppb) and asthma patients (780 [619-961] ppb) (both p < 0.001). FeNO positively related to FEV1 (rho = 0.51, p = 0.001) in CF patients and this was consistent in both adults and children. A negative correlation was found between FeNO and blood neutrophil counts (rho = -0.37, p = 0.03) in CF patients.CONCLUSION: CF patients have lower FeNO and nNO and similar CalvNO levels as healthy controls and asthma patients. Lower FeNO related to lower lung function in both adults and children with CF. Furthermore, in CF, lower FeNO also related to higher blood neutrophil counts.
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| 13. |
- Perez-Bogerd, Silvia, et al.
(författare)
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COPD patients with peripheral airway obstruction reversibility identified by exhaled nitric oxide
- 2019
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 13:3
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Tidskriftsartikel (refereegranskat)abstract
- Rationale:Besides its role as an inflammatory marker in asthma, fractional exhaled nitric oxide (FENO) provides information on the extent of the airway obstruction process through evaluating its change after bronchodilation.Objective:To investigate whether FENO change after bronchodilation can identify different sites of airway obstruction in COPD patients.Methods:FENO, FEV(1 )and the slopes (S) of the alveolar plateau of the single breath washout test (SBWT) were measured in 61 stable COPD patients (FEV1 34.5% predicted) before and after the inhalation of 400 mu g salbutamol. SBWT used Helium (He), and sulfur-hexafluoride (SF6). Obstruction relief occurring in pre-acinar and intra-acinar small airways is expected to decrease S-He and S-F6 , respectively. Indices changes (Delta) after bronchodilation were expressed as a percentage of pre-bronchodilation values.Results:FENO stability (vertical bar Delta FENO vertical bar <= 11%) was observed in 19 patients [-2.7(6.7)%] [mean (SD)] (NO = group); Delta FENO > 11% [+37.4(27.7)%] in 20 patients (NO+group) and Delta FENO < -11% in 22 patients [-31.2(9.8)%] (NO- group). A similar Delta FEV1 (p = 0.583; [+9.4(9.6)%]) was found in the three groups. In NO = and NO+ groups, neither S-He nor S-SF6 changed; in NO- both S-He [-12.4(27.5)%, p = 0.007] and S-SF6 [ -20.2(20.4)%, p < 0.001] significantly decreased.Conclusion:Different patterns of FENO response to beta(2) -agonists were observed in COPD most likely depending on the extent of the dilation process. A profile of airway obstruction with an extensive beta(2) -agonist response down to lung periphery is identified by FENO reduction after acute bronchodilation in 30% of COPD patients. The clinical relevance of this profile requires further investigation.
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| 14. |
- Ricciardolo, Fabio Luigi Massimo, et al.
(författare)
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Nitric oxide's physiologic effects and potential as a therapeutic agent against COVID-19
- 2021
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Ingår i: Journal of Breath Research. - : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 15:1
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Forskningsöversikt (refereegranskat)abstract
- The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for COVID-19 pneumonia, a pandemic that precipitates huge pressures on the world's social and economic systems. Disease severity varies among individuals. SARS-CoV-2 infection can be associated with e.g. flu-like symptoms, dyspnoea, severe interstitial pneumonia, acute respiratory distress syndrome, multiorgan dysfunction, and generalized coagulopathy. Nitric oxide (NO), is a small signal molecule that impacts pleiotropic functions in human physiology, which can be involved in the significant effects of COVID-19 infection. NO is a neurotransmitter involved in the neural olfactory processes in the central nervous system, and some infected patients have reported anosmia as a symptom. Additionally, NO is a well-known vasodilator, important coagulation mediator, anti-microbial effector and inhibitor of SARS-CoV replication. Exhaled NO is strongly related to the type-2 inflammatory response found in asthma, which has been suggested to be protective against SARS-CoV-2 infection. Several reports indicate that the use of inhaled NO has been an effective therapy during this pandemic since the ventilation-perfusion ratio in COVID-19 patients improved afterwards and they did not require mechanical ventilation. The aim of this mini-review is to summarize relevant actions of NO that could be beneficial in the treatment of COVID-19.
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| 15. |
- Soares, M., et al.
(författare)
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Particles in exhaled air (PExA): non-invasive phenotyping of small airways disease in adult asthma
- 2018
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 12:4
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: Asthma is often characterised by inflammation, damage and dysfunction of the small airways, but no standardised biomarkers are available. Objectives: Using a novel approach-particles in exhaled air (PExA)-we sought to (a) sample and analyse abundant protein biomarkers: surfactant protein A (SPA) and albumin in adult asthmatic and healthy patients and (b) relate protein concentrations with physiological markers using phenotyping. Methods: 83 adult asthmatics and 21 healthy volunteers were recruited from a discovery cohort in Leicester, UK, and 32 adult asthmatics as replication cohort from Sweden. Markers of airways closure/small airways dysfunction were evaluated using forced vital capacity, impulse oscillometry and multiple breath washout. SPA/albumin from PEx (PExA sample) were analysed using ELISA and corrected for acquired particle mass. Topological data analysis (TDA) was applied to small airway physiology and PExA protein data to identify phenotypes. Results: PExA manoeuvres were feasible, including severe asthmatic subjects. TDA identified a clinically important phenotype of asthmatic patients with multiple physiological markers of peripheral airway dysfunction, and significantly lower levels of both SPA and albumin. Conclusion: We report that the PExA method is feasible across the spectrum of asthma severity and could be used to identify small airway disease phenotypes.
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| 16. |
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| 17. |
- Cristescu, S. M., et al.
(författare)
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Methods of NO detection in exhaled breath
- 2013
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 7:1, s. 017104-
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Tidskriftsartikel (refereegranskat)abstract
- There is still an unexplored potential for exhaled nitric oxide (NO) in many clinical applications. This study presents an overview of the currently available methods for monitoring NO in exhaled breath and the use of the modelling of NO production and transport in the lung in clinical practice. Three technologies are described, namely chemiluminescence, electrochemical sensing and laser-based detection with their advantages and limitations. Comparisons are made in terms of sensitivity, time response, size, costs and suitability for clinical purposes. The importance of the flow rate for NO sampling is discussed from the perspective of the recent recommendations for standardized procedures for online and offline NO measurement. The measurement of NO at one flow rate, such as 50 ml s(-1), can neither determine the alveolar site/peripheral contribution nor quantify the difference in NO diffusion from the airways walls. The use of NO modelling (linear or non-linear approach) can solve this problem and provide useful information about the source of NO. This is of great value in diagnostic procedures of respiratory diseases and in treatment with anti-inflammatory drugs.
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| 18. |
- Högman, Marieann, et al.
(författare)
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A practical approach to the theoretical models to calculate NO parameters of the respiratory system
- 2014
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Ingår i: Journal of breath research. - : IOP Publishing. - 1752-7163 .- 1752-7155. ; 8:1, s. 016002-
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Tidskriftsartikel (refereegranskat)abstract
- Expired nitric oxide (NO) is used as a biomarker in different respiratory diseases. The recommended flow rate of 50 mL s⁻¹ (F(E)NO₀.₀₅) does not reveal from where in the lung NO production originated. Theoretical models of NO transfer from the respiratory system, linear or nonlinear approaches, have therefore been developed and applied. These models can estimate NO from distal lung (alveolar NO) and airways (bronchial flux). The aim of this study was to show the limitation in exhaled flow rate for the theoretical models of NO production in the respiratory system, linear and nonlinear models. Subjects (n = 32) exhaled at eight different flow rates between 10-350 mL s⁻¹ for the theoretical protocols. Additional subjects (n = 32) exhaled at tree flow rates (20, 100 and 350 mL s⁻¹) for the clinical protocol. When alveolar NO is calculated using high flow rates with the linear model, correction for axial back diffusion becomes negligible, -0.04 ppb and bronchial flux enhanced by 1.27. With Högman and Meriläinen algorithm (nonlinear model) the corrections factors can be understood to be embedded, and the flow rates to be used are ≤20, 100 and ≥350 mL s⁻¹. Applying these flow rates in a clinical setting any F(E)NO can be calculated necessitating fewer exhalations. Hence, measured F(E)NO₀.₀₅ 12.9 (7.2-18.7) ppb and calculated 12.9 (6.8-18.7) ppb. In conclusion, the only possibility to avoid inconsistencies between research groups is to use the measured NO values as such in modelling, and apply tight quality control to accuracies in both NO concentration and exhaled flow measurements.
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| 19. |
- Högman, Marieann, et al.
(författare)
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Extended NO analysis in asthma
- 2007
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 1:2, s. 024001-
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Forskningsöversikt (refereegranskat)abstract
- The discovery of the flow dependence of exhaled NO made it possible to model NO production in the lung. The linear model provides information about the maximal flux of NO from the airways and the alveolar concentrations of NO. Nonlinear models give additional flow-independent parameters such as airway diffusing capacity and airway wall concentrations of NO. When these models are applied to patients with asthma, a clear-cut increase in NO flux is found, and this is caused by an increase in both airway diffusing capacity and airway wall concentrations of NO. There is no difference in alveolar concentrations of NO compared to healthy subjects, except in severe asthma where an increase has been found. Inhaled corticosteroids are able to reduce the airway wall concentrations but not diffusing capacity or alveolar concentrations. Oral prednisone affects the alveolar concentration, suggesting that in severe asthma there is a systemic component. Steroids distributed by any route do not affect the airway diffusing capacity. Therefore, the airway diffusing capacity should be in focus in testing new drugs or in combination treatment for asthma. Exhaled NO analysis is a promising tool in characterizing asthma in both adults and children. However, there is a strong need to agree on the models and to standardize the flow rates to be used for the modelling in order to perform a systematic and robust analysis of NO production in the lung.
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| 20. |
- Högman, Marieann
(författare)
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Extended NO analysis in health and disease
- 2012
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Ingår i: Journal of breath research. - : IOP Publishing. - 1752-7163 .- 1752-7155. ; 6:4, s. 047103-
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Tidskriftsartikel (refereegranskat)abstract
- Extended NO analysis is a promising tool in different diseases where NO metabolism is altered. One single exhalation cannot give insight to the NO production in the respiratory system; rather the use of multiple exhalation flows can give the alveolar levels (CANO), airway wall concentration (CawNO) and the diffusion rate of NO (DawNO). Increased values of CANO are shown in COPD, systemic sclerosis, hepatopulmonary syndrome and in severe asthma. In asthma the CawNO and DawNO are increased leading to an increase in bronchial NO flux (J'awNO). Low levels of J'awNO are seen in cystic fibrosis, primary ciliary dyskinesia and in smoking subjects. More studies are needed to evaluate the clinical usefulness of the extended NO analysis, similar to what has been done in systemic sclerosis where a cut-off value has been identified predicting pulmonary function deterioration.
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| 21. |
- Jacinto, Tiago, et al.
(författare)
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Evolution of exhaled nitric oxide levels throughout development and aging of healthy humans
- 2015
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- It is not fully understood how the fraction of exhaled nitric oxide (FeNO) varies with age and gender in healthy individuals. We aim to describe the evolution of FeNO with age, giving special regard to the effect of gender, and to relate this evolution to natural changes in the respiratory tract. We studied 3081 subjects from NHANES 2007-08 and 2009-10, aged 6-80 years, with no self-reported diagnosis of asthma, chronic bronchitis or emphysema, and with normal values of blood eosinophils and C-reactive protein. The relationship of the mean values of FeNO to age, in all participants and divided by gender, was computed, and compared with changes in anatomic dead space volume and forced vital capacity. A change-point analysis technique and subsequent piecewise regression was used to detect breakpoints in the evolution of FeNO with age. Three distinct phases in the evolution of FeNO throughout the age range 6-80 years can be seen. FeNO values increase linearly between 6-14 years of age in girls and between 6-16 years of age in boys, in parallel with somatic growth. After that, FeNO levels plateau in both genders until age 45 years in females and age 59 years in males, when they start to increase linearly again. This increase continues until age 80. Our data clearly show a triphasic evolution of FeNO throughout the human age range in healthy individuals. This should be accounted for in development of reference equations for normal FeNO values.
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| 22. |
- Jones, A Wayne, et al.
(författare)
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Determination of ethanol in breath for legal purposes using a five-filter infrared analyzer : studies on response to volatile interfering substances
- 2008
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Ingår i: JOURNAL OF BREATH RESEARCH. - : Institute of Physics. - 1752-7155 .- 1752-7163. ; 2:2
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Tidskriftsartikel (refereegranskat)abstract
- The analysis of ethanol in exhaled breath is widely accepted and used worldwide for legal purposes to gather evidence of alcohol-impaired driving. Most evidential breath-alcohol instruments incorporate infrared (IR) spectroscopy as the analytical principle focusing on C-H or C-O stretching frequencies in ethanol molecules. The instrument approved for legal purposes in Sweden is called Evidenzer and is equipped with five infrared filters of which four are used for identification and quantification of ethanol and the fifth is a reference filter. The response of Evidenzer was tested against 21 volatile organic compounds (VOCs), and the instrument was programmed to deduct any bias caused by these VOCs if present in a sample of breath. If the amount deducted exceeds a certain threshold value, the entire test is aborted. Whenever this happens, the police request a specimen of venous blood for analysis by gas chromatography. Of a total of 24 072 drunken drivers, the evidential breath-alcohol test was aborted on 27 occasions (0.11%) because an interfering substance was present above the critical threshold. The VOCs most commonly identified in blood were acetone, isopropanol and/or methyl ethyl ketone (MEK). Elevated levels of acetone and isopropanol might arise during ketogenesis in people suffering from diabetes, or in those who eat low carbohydrate diets. High concentrations of acetone and MEK are probably caused by people drinking a technical alcohol product (T-Red), which is available in Sweden and is denatured with these agents. This study confirms that relatively few apprehended drivers in Sweden have elevated concentrations of VOCs in breath other than ethanol. Even the aborted breath tests, to a large extent, contained ethanol above the legal limit for driving.
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| 23. |
- Kaisdotter Andersson (Jonsson), Annika, et al.
(författare)
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Methodology investigation of expirograms for enabling contact free breath alcohol analysis
- 2009
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 3:3, s. 036002-
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Tidskriftsartikel (refereegranskat)abstract
- The present techniques for breath alcohol determination have usability limitations concerning practical use and the time and effort required for the test person. The rationale of the physiological assumptions in a recently demonstrated technique for breath analysis without a mouthpiece is investigated in this paper. Expirograms quantifying ethanol, carbon dioxide (CO2) and water (H2O) from 30 test subjects were analysed, with respect to the influence of individual variations in end-expiratory CO2 and H2O concentrations, and possible benefits from simultaneous measurement of CO2 or H2O. Both healthy subjects and patients suffering from pulmonary diseases performed breath tests with small and maximum volume expiration. The breath tests were recorded basically with a standard evidential instrument using infrared absorption spectroscopy, and equipped with a mouthpiece. Average concentrations were significantly higher for the maximum than for the small expirations. For the maximum expirations, the healthy subjects had a significantly higher end-expired PCO2 of 4.4 ± 0.5 kPa (mean ± standard deviation) than the patients (3.9 ± 0.7 kPa). The corresponding values for H2O were 39 ± 1 and 38 ± 1 mg l−1. The results indicate that the CO2 variability is consistent with the requirements of accuracy for alcohol ignition interlocks. In addition, CO2 as tracer gas is preferable to H2O due to its low concentration in ambient air. In instruments for evidential purposes H2O may be required as tracer gas for increased accuracy. Furthermore, the study provides support for early determination of breath alcohol concentration, indicating that determination after 2 s will introduce an additional random error of 0.02 mg l−1 or less.
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| 24. |
- Krantz, Christina, et al.
(författare)
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Nasal nitric oxide is associated with exhaled NO, bronchial responsiveness and poor asthma control
- 2014
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Ingår i: Journal of Breath Research. - : IOP Publishing. - 1752-7155 .- 1752-7163. ; 8:2, s. 026002-
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Tidskriftsartikel (refereegranskat)abstract
- The fraction of exhaled nitric oxide (FeNO) is an established marker of airway inflammation in asthma. Nasal nitric oxide (nNO) has initially been regarded as a promising marker of inflammation of nasal mucosa. However, due to its dual origins, paranasal sinuses and nasal mucosa, the clinical use of nNO is controversial. There is an inflammatory link between inflammation in the upper and lower airways within the united airways' paradigm, but the study of the clinical value of nNO in asthma has been limited. The objective of this study is to analyse nNO in asthmatics and its relationship to FeNO, bronchial hyperresponsiveness, allergic sensitization and asthma control. A total of 371 children and young adults from an asthma cohort were included in this study, which performed measurements of nNO (through aspiration at 5 mL s(-1)), FeNO, bronchial responsiveness to methacholine, blood eosinophil count (B-Eos) and IgE sensitization. The asthma control test (ACT) and a questionnaire regarding medical treatment, symptoms of asthma, rhinitis and chronic rhinosinusitis were completed by all subjects. An association was found between higher nNO levels and increased bronchial responsiveness (p < 0.001), FeNO (p < 0.001) and B-Eos (p = 0.002). Sensitization to furry animals related to higher levels of nNO (p < 0.001). Subjects with poorly controlled asthma (ACT < 15) had lower levels of nNO than subjects with a higher ACT score (619 +/- 278 ppb, versus 807 +/- 274 ppb, p = 0.002). Loss of smell showed the strongest association with lower nNO levels among the upper airway symptoms recorded. In patients with asthma, nNO was positively correlated with exhaled NO, bronchial responsiveness and asthma control. This study suggests clinical utility of nNO in subjects with asthma, but in order to get better understanding of the nNO determinants, simultaneous mapping of upper airway comorbidities by clinical examination is appropriate.
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| 25. |
- Metsälä, Markus, et al.
(författare)
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Acetylene in breath : background levels and real-time elimination kinetics after smoking
- 2010
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Ingår i: Journal of Breath Research. - Bristol, UK : Institute of Physics Publishing (IOPP). - 1752-7155 .- 1752-7163. ; 4:4
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Tidskriftsartikel (refereegranskat)abstract
- We have measured the acetylene concentration in the exhaled breath of 40 volunteers (31 non-smokers, nine smokers) using near-infrared cavity ring-down spectroscopy. The acetylene levels were found to be the same as in ambient air for non-smokers, whereas elevated levels were observed for smokers. Real-time measurements with sub-second time resolution have been applied to measure the elimination kinetics of acetylene in breath after exposure to tobacco smoke. Three exponential time constants can be distinguished from the data and these can be used to define the residence times for different compartments, according to the multi-compartment model of the human body.
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